Pyridyl amines have been used to prepare Group 4 complexes, which are useful transition metal components in the polymerization of alkenes, see for example, US 2002/0142912, U.S. Pat. No. 6,900,321, and U.S. Pat. No. 6,103,657, where the ligands have been used in complexes in which the ligands are coordinated in a bidentate fashion to the transition metal atom.
WO 2005/095469 shows catalyst compounds that use tridentate ligands through two nitrogen atoms (one amido and one pyridyl) and one oxygen atom.
US 2004/0220050A1 and WO 2007/067965 disclose group 4 transition metal pyridylamide complexes in which the ligand is coordinated in a tridentate fashion through two nitrogen (one amido and one pyridyl) and one carbon (aryl anion) donor. The amido donor in these complexes does not coordinate to the transition metal with the formation of a 7-membered ring.
A key step in the activation of these complexes is the insertion of an alkene into the metal-aryl bond of the catalyst precursor (Froese, R. D. J. et al., J. Am. Chem. Soc., 2007, Vol. 129, pp. 7831-7840) to form an active catalyst. The coordination of the amido donor group in these complexes forms a 5-membered ring instead of a 7-membered ring.
U.S. Pat. No. 7,973,116 B2 discloses group 4 pyridyldiamide complexes that are useful as catalyst components for olefin polymerization processes. These complexes feature tridentate dianionic ligands that coordinate to the metal center through three nitrogen donor groups.
Other references of interest include: 1) Domski, G. J.; Rose, J. M.; Coates, G. W.; Bolig, A. D.; Brookhart, M., “Living alkene polymerization: New methods for the precision synthesis of polyolefins,” Prog. Polym. Sci., 2007, Vol 32, pp. 30-92; 2) Giambastiani, G.; Laconi, L.; Kuhlman, R. L.; Hustad, P. D., “Imino- and amido-pyridinate d-block metal complexes in polymerization/oligomerization catalysis,” Chapter 5 in Olefin Upgrading Catalysis by Nitrogen-based Metal Complexes I, Catalysis by Metal Complexes, Springer, 2011; 3) Vaughan, A; Davis, D. S.; Hagadom, J. R., “Industrial catalysts for alkene polymerization”, Comprehensive Polymer Science, 2012, Vol. 3, Chapter 20; 4) Gibson, V. C.; Spitzmesser, S. K. Chem. Rev., 2003, Vol. 103, p. 283; 5) Britovsek, G. J. P.; Gibson, V. C.; Wass, D. F.; Angew. Chem. Int. Ed., 1999, Vol. 38, p. 428; 6) WO 2010/037059; 7) Boussie, Thomas R. et al. “Nonconventional Catalysts for Isotactic Propene Polymerization in Solution Developed by Using High-Throughput-Screening Technologies” Angew. Chem. Int. Ed. 2006, 45, 3278-3283; 8) U.S. Pat. No. 8,674,040; and 9) U.S. Pat. No. 7,087,690.
There still is need for new catalysts complexes with enhanced performance in alkene polymerization.
Further, there is a need in the art for new catalysts that are capable of producing high molecular weight polymers at high process temperatures, including highly crystalline polypropylene and ethylene copolymers with alpha olefins.